Currently, medicines of high molecular weight are administered by an intravenous or subcutaneous injection for treatment. Administration of medicines of high molecular weight by injection is difficult for patients to perform by themselves and is accompanied by pain. It is hoped, therefore, to employ transmucosal administration as an alternative and easier method of administration. Examples of transmucosal administration include administration through the mucosa of digestive tracts such as the stomach, small intestine, large intestine, and rectum, as well as the nose, eye, mouth, lung, and vagina. Administration through the nasal mucosa, among others, is gaining attention as a relatively easy method of administration, which allows for quick absorption of the drug and reliable effects.
The applicant has found that the difficulty associated with absorption of a medicine of high molecular weight, contained in a powdery preparation for transmucosal administration and absorbed through mucosa, can be significantly reduced by providing the medicine of high molecular weight with a cationic polymer (and additionally a viscous polymer, if necessary) (International Application No.: WO 00/02574).
The applicant has since made a continuous effort to find ways of improving the storage stability of the preparation.
It is therefore an object of the present invention to provide a powdery preparation for transmucosal administration comprising a medicine of high molecular weight and a cationic polymer in which the storage stability of the medicine of high molecular weight is improved while maintaining the improved transmucosal absorption of the medicine of high molecular weight.